自适应最小均方算法的本质

本文指出最小均方算法并不能使均方误差最小,证明了最小均方算法实际上是一种加权最小二乘算法。     

An optical sensor for hydrogen sulfide detection in open path using WMS-2f/1f technique

An optical hydrogen sulfide (H2S) sensor based on wavelength modulation spectroscopy with the second harmonic (2f) corrected by the first harmonic (1f) signal (WMS-2f/1f) is developed using a distributed feedback (DFB) laser emitting at 1.578 µm and a homemade gas cell with 1-m-long optical path length. The novel sensor is constructed by an electrical cabinet and an optical reflecting and receiving end. The DFB laser is employed for targeting a strong H2S line at 6 336.62 cm-1 in the fundamental absorption band of H2S. The sensor performance, including the minimum detection limit and the stability, can be improved by reducing the laser intensity drift and common mode noise by means of the WMS-2f/1f technique. The experimental results indicate that the linearity and response time of the sensor are 0.999 26 and 6 s (in concentration range of 15.2—45.6 mg/m3), respectively. The maximum relative deviation for continuous detection (60 min) of 30.4 mg/m3 H2S is 0.48% and the minimum detection limit obtained by Allan variance is 79 μg/m3 with optimal integration time of 32 s. The optical H2S sensor can be applied to environmental monitoring and industrial production, and it has significance for real-time online detection in many fields.     

重新认识自适应LMS算法

旧的关于LMS算法的理论不能解释信号对消现象及某些情况下的收敛特性。本文以误差样本平方的时间平均为目标函数,重新导出了LMS算法,并分析了其瞬态及稳态特性,使理论和实际达到了圆满的统一。     

自适应SLC系统的方向性隐零点

本文通过对自适应旁瓣对消系统(SLC)的方向性图的分析,证明了位于干扰方向的隐零点的存在,首次得出了用单辅助天线即可对付多干扰这一重要结论.     

Research on high-precision hole measurement based on robot vision method

A high-precision vision detection and measurement system using mobile robot is established for the industry field de- tection of motorcycle frame hole and its diameter measurement. The robot path planning method is researched, and the non-contact measurement method with high precision based on visual digital image edge extraction and hole spatial circle fitting is presented. The Canny operator is used to extract the edge of captured image, the Lagrange interpolation algorithm is utilized to determine the missing image edge points and calculate the centroid, and the least squares fitting method is adopted to fit the image edge points. Experimental results show that the system can be used for the hi gla-precision real-time measurement of hole on motorcycle frame. The absolute standard deviation of the proposed method is 0.026 7 mm. The proposed method can not only improve the measurement speed and precision, but also re- duce the measurement error.     

空间域和时域信号的正交化预处理

本文给出了空间域和时域信号处理系统中正交化预处理网络的结构和分析,并讨论了两者在结构上的极大差异。     

自适应LMS算法均方误差收敛的充分条件

本文给出了保证自适应最小均方算法均方误差(或平均功率)收敛的充分条件,并分析了在该条件下均方误差的收敛性能。     

自适应性SLC的实际性能

本文论证了自适应天线旁瓣对消器(SLC)的对消性能取决于主、辅天线信号或干扰及有用信号的相干特性,而和统计相关性无直接关系。     

A 3D measurement method based on multi-view fringe projection by using a turntable

In order to get the entire data in the optical measurement, a multi-view three-dimensional (3D) measurement method based on turntable is proposed. In the method, a turntable is used to rotate the object and obtain multi-view point cloud data, and then multi-view point cloud data are registered and integrated into a 3D model. The measurement results are compared with that of the sticking marked point method. Experimental results show that the measurement process of the proposed method is simpler, and the scanning speed and accuracy are improved.